Integration with postfix and cyrus

Hello, I would like to use ldap with postfix and cyrus for a site with
many virtual domains (e-mail only), can any1 tell me which objectclass
should I use for users. what I need is something like:
o=myorganization
|
--ou=students
| |
| - cn=user1(with field for email address(virtual),
| mail backend, passwd, bla, bla bla.)
|
|_ou=teachers (something similar)
can you give me any clue?
Thanx
--
Jorge Calas Lozano
Proud Linux User #182341
Since October 1999
SysAdmin @ fcf.uh.cu
((o]<